A fuel pump is a key component in the fuel lines which are the veins of your car. Knowing the fuel pump replacement cost, how often should it be changed, and how to spot a faulty fuel pump will always come in handy. First, let’s look at some numbers.
On average, close to 400 million gallons of gasoline is being used in the US alone. The amount of cars on the road is at an all-time high and the numbers are increasing daily. All things considered, people are spending more time in the gas station than ever before.
Typically, a car in the U.S.A travels 13500 miles in a single year. With an average fuel economy of a vehicle being 22 miles per gallon, we each burn through over 500 gallons of gasoline annually. This means 500 gallons is pumped into your fuel tanks and every bit of it needs to make its way to the engine. It is imperative that we spend time understanding how the fuel system of the car works. The fuel pump plays a vital role in getting the fuel from your tank to your engine.
What Is A Fuel Pump
A fuel pump is a mechanical or electrical device placed away from the engine block and more towards the fuel tank. Most fuel pumps in modern cars use electronic fuel pumps instead of mechanical fuel pumps.
Electrical Fuel Pump
An electric fuel pump is going to offer increased pressure more than a mechanical pump. Electric pumps offer a larger variety of flow rates and pressure outputs in comparison to mechanical pumps. An electric fuel pump will be necessary with boosted applications, nitrous, and fuel injection. The majority of electric pumps in the market use a 12V battery with the addition of a relay system which gives multiple shut-off options.
Mechanical Fuel Pump
A mechanical fuel pump is much more convenient and cheaper when compared to an electric fuel pump. Mechanical pumps are quieter and are easier to install since there are no wires involved. Considering that a mechanical fuel pump can manage a load up to a 450hp engine, it’s a perfectly fine choice for an ordinary daily driver since it is easy to install and very reliable as well.
What Is The Function Of A Fuel Pump?
Easy, to pump fuel, right? Yeah, that is about it.
The engine requires a constant supply of fuel to keep working. Fuel reserves are provided by the fuel that you pump to your fuel tank. The fuel pump is tasked with getting your fuel from the tank to the engine.
The fuel pump needs to get the fuel to the combustion chamber. This is where the fuel is mixed with air. After that, the engine will work to compress it and ignite the mixture.
Here again, the way the fuel pump works both between mechanical pumps and electrical pumps differ from one another.
Mechanical Fuel Pump
A mechanical pump is driven by the camshaft or on some occasions a special shaft driven by the crankshaft. As the shaft turns, a cam passes under a pivoted lever and forces it up at one end.
The lever is linked to a rubber diaphragm which forms the bottom layer of the chamber, goes down with the lever. The suction created during this process is enough to pull the gasoline through a one-way valve.
As the revolving cam turns further and no longer presses on the lever, here a return spring moves the lever back, relieving the pressure from the diaphragm.
When the diaphragm goes down, the fuel that was pulled in is pressurized. Since it can not go back through the one-way valve, it moves through another valve that leads to the combustion chamber.
Electrical Fuel Pump
The process of an electronic fuel pump is similar to a mechanical fuel pump. The same diaphragm action is consistent. But instead of the camshaft, a solenoid which is an electromagnetic switch pulls the diaphragm.
The solenoid turns on to pull a metal rod to expand the diaphragm. And similarly, gasoline enters the fuel line through a valve.
At the peak of the diaphragm’s expansion, the metal rod is attracted close enough to set apart a couple of contacts seizing the actions of the electromagnet. As the metal rod returns to its initial position the diaphragm constricts sending the fuel through another valve into the combustion chamber.
Most mechanical and electrical fuel pumps are made to send fuel as required. In an alternate system, the fuel is constantly circulated through a network of pipes and the engine takes in fuel as it requires.
Signs That Indicate Your Fuel Pump Is Going Bad
Knowing what to look for could tell you the right moment when a fuel pump needs to be replaced. You would be able to pinpoint the problem rather than misdiagnosing it as an engine or transmission failure. A fuel pump replacement cost is relatively small than repairing an engine or a transmission.
Car Jerks Or Sputters At High Speeds
When driving at higher speeds, the engine will require more fuel than usual. You will mostly be able to notice this while driving on a freeway since you’d be driving faster than usual.
The problem is caused when the fuel pump can not deliver a smooth flow of fuel to the engine as required. When this happens, the engine only receives mostly air instead of a balanced mixture of fuel and air. This leaves the engine not being able to produce enough power, causing the engine to sputter and jerk.
The sputtering might not last long. Usually, it lasts only for a minute or less. A common mistake most drivers make is assuming that the cause of this is bad fuel quality. Even though bad fuel quality will give the same symptoms, modern fuel standards are pretty high. Therefore, the engine sputters due to the fuel quality is highly unlikely. The most probable cause would be the fuel pump.
Losing Power During Acceleration
If you notice that your car often loses power when you try to accelerate from a stop, your fuel pump may be in trouble. Understanding the physics behind acceleration allows us to realize that accelerating requires much more force than traveling at a constant speed, even if it is much higher than the speeds we are accelerating.
To generate much more energy to accelerate the car, the engine is going to need more fuel than usual. This will force your fuel pump to work harder. A failing fuel pump will not be able to keep up with this demand and your car would struggle to accelerate.
When the engine is starved of fuel when it tries to accelerate, that would cause the engine to shut down.
Trouble Driving Uphill
Driving through a higher incline certainly puts extra strain on the engine. The engine, to overcome this trouble, will try to resolve it by generating more power.
If the fuel pump is not up to the task the engine will not get the juice to generate the power needed to get you over that hill.
A faulty fuel pump means the engine would lose power and eventually stall mid-way through the incline.
Increase In Temperature
With a malfunctioning fuel pump, it is common that the vehicle temperature rises. Since a lot of issues could cause an increase in temperature, it’s hard to diagnose the cause even if the error is caused by the fuel pump.
Looking out for other signs with the combination of overheating will allow you to conclude that the problem is the fuel pump.
Problem With The Fuel Pressure Gauge
The fuel pressure gauge of your car indicates the amount of fuel supplied to your engine and the pressure it is supplied with. The amount of fuel the engine needs differs according to the vehicle.
The best way to find the amount of fuel your car needs is by revising the user manual. Once you know what you are looking for, check the pressure gauge. If the value you see is lower than advised it’s certain that your fuel pump is faulty.
Unable To Haul Heavy Cargo
Again, the fact that your engine cannot produce enough power affects its performance. With a heavy load or if you were towing something, your engine won’t be able to cope with the stress without getting enough fuel.
This would eventually lead your engine to an abrupt stop.
Engine Surges
As your fuel pump begins to wear out, its components often wear down at different rates. When the mismatch is great enough, the pressure in your fuel lines becomes inconsistent sending fuel to the engine more or less than necessary.
When this happens drivers might encounter their cars accelerating forward even though they don’t press the gas pedal. This momentary acceleration is known as ‘surging’.
Decreased Fuel Efficiency
Your fuel pump has a relief valve that controls the amount of fuel that enters the engine. If this relief valve does not function properly your engine will drink more fuel than needed.
You could imagine that with more fuel your engine might be able to produce more power. But increased amount of fuel in the engine block is worthless without more air. Your engine will not receive all the air required to burn the fuel. So the excess fuel the engine receives will be unburnt and is to be wasted anyway.
So, if your car’s fuel economy has dropped significantly in a short period of time, taking a look at the fuel pump is certainly worth it.
Unusual Noises From The Fuel Tank
Every car owner knows whenever they hear a sound that is not suitable for a finely working car, there is something wrong with it. The same implies with the fuel pump as well
Usually, the fuel pump will make a smooth a barely audible humming noise. But when it’s faulty, the humming noise intensifies and you’ll be able to hear more of a whining noise.
This could either mean that your reserves are over and the fuel pump is sucking in fumes or a broken fuel pump.
Engine Won’t Start
Fuel must get into your engine for it to start. In ordinary circumstances, you turn the key, fuel gets into the engine and voila, we’ve got ignition.
When your fuel pump is broken or it is not delivering fuel at enough pressure your car won’t start. You would need to turn the key a few times and listen to an engine struggling to start for a while. After a few cranks, there will be enough fuel to fire up the engine. It is just going to take a while.
What Happens When Your Fuel Pump Stops Working?
What happens if you do not see any of the above signs or just decide to ignore them? Your engine will not get fuel and it’s just a matter of time before your car stalls.
After you ignore all these signs, your fuel pump is completely busted. Next, it just so happens that no fuel will ever reach your engine. No matter how hard you try, even if you pour an entire gallon into your tank there is no way to start a car without a fuel pump.
When you turn the key you may hear the spark plugs firing but without fuel, it is going to be no use.
There could always be other reasons that are causing your engine to fail. If you want to make sure it is the fuel pump that is causing the issue, you can check the pressure on the fuel lines using a fuel pressure gauge. If the reading comes out as zero that can only mean you have a dead pump on your hands.
Reasons Leading To Fuel Pump Damage
Rust
As with every component of any car, rust is always a killer. The same is true with the fuel pump as well. Rust and sometimes even dust can bypass the inlet filter sock which is the device that is supposed to filter dust and other contaminated particles from infiltrating the fuel pump. But when these particles enter the fuel pimp it ends up causing a jam. As a result, a breakdown happens and this also increases the temperature of the motor.
Usage
Wear and tear are inevitable. There is no way to protect these parts from wear as long as we use our car. This is more common with electric fuel pumps in which roller gears, brushes, armature, bearings, and pump vanes all experience heavy wear and tear. This causes a loss of pressure with which the electric pump can supply the engine with.
Inadequate Supply Of Fuel
If the vehicle has not been used for a longer period of time the fuel pump will be drained of any fuel left in it. Fuel actually works as the lubricant as well as the coolant for the fuel pump. If the fuel pump is starved from fuel damage is unavoidable.
Fuel Pump Replacement Cost
Many factors could determine your fuel pump replacement cost. Labor and the actual cost of the fuel pump can end up adding up to $700.
Price Of The Fuel Pump
The price of a fuel pump depends on the brand, model, and year of your vehicle. A fuel pump for a BMW 750i would cost somewhere close to $475. For a Mercedes-Benz CL600, this would cost $350 for a new pump while a Kia Rio would cost you just around $225. As mentioned, it mainly depends on the brand and the model of the car.
Overall, a fuel pump replacement cost will be between $150 to $500 without labor.
Labor Costs
There is standard pricing for labor. For most garages in the US, labor costs are between $70 and $160. It averages around $90 per hour. When it comes to fuel pump replacement cost in the labor department, it again depends on the type of fuel pump you are going to install.
A mechanical fuel pump will take no more than an hour to install. In the meantime, an electric fuel pump could take 2 to 3 hours. So that multiplied with the average labor costs per hour or the prices in your area would give you an idea of the final bill you could receive once you set out to replace a fuel pump.
How To Replace A Fuel Pump
Replacing an electronic fuel pump is much harder than replacing a mechanical fuel pump. It is advised to go to a mechanic when it comes to replacing an electrical fuel pump.
This doesn’t mean you can not try to replace a mechanical fuel pump. If you have the time it is certainly worth it. Professionals are capable of switching a mechanical fuel pump in less than 45 minutes. This does not mean you will be able to do it in the same time frame as well.
Most rookies take around 3 to 5 hours to achieve this. It is not something to be ashamed of since we are new to the field and learning every step of the way. If you do have the courage to try something new, the time on your hands, and a few handy tools, it’s possible to replace a fuel pump yourself.
Replacing A Mechanical Fuel Pump
Caution: Remember that you will be working with a lot of fuel around the workplace and often surrounded by fuel vapor as well. Make sure to start in a well-ventilated area. Do not smoke or start any naked flames since they could be a safety hazard.
Once you’ve gathered your tools, turn off your vehicle, and made sure you’re working in a safe area, you can begin working.
First off, the old fuel pump needs to be removed.
- Remove the battery cable.
- Disconnect the fuel tank hose at the fuel pump. You may notice fuel gushing out. Stop the flow by plugging the hose with a bolt or a wooden dowel. Also, remove the vapor return hose as well.
- Examine the old fuel hose. If you see a crack on it, replace it with a new fuel hose.
- Disconnect the outlet line to the carburetor. Use a wrench on the fuel pump fitting and another on the line nut.
- Remove the 2 attaching bolts and extract the old fuel pump. Clean off any gasket material from the mounting surface of the engine.
Now that is done and the old fuel pump is removed, it’s time to equip the new one.
- Apply a coat of gasket sealer over the gasket and attach the bolts through the pump and slip the gasket over the bolts
- Install the new pump on the engine. Make sure that the pushrod is correctly installed in both the engine and the fuel pump.
- Attach the fuel outlet line that runs to the carburetor. If you find it difficult to connect this, remove the other end of the line from the carburetor. Connect the line to the fuel pump, and then reattach the other end to the carburetor.
- Attach the fuel inlet hose from the gas tank and the vapor-return hose. Tighten all clamps.
- Reconnect the battery. Try starting the car and check for any leaks.
And that’s it. You’ve now successfully switched out the fuel pump.
Fuel Pump: Facts You Need to Know
- A fuel pump is a vital part of a vehicle’s internal combustion engine system that delivers fuel to the engine with sufficient pressure.
- In older, carbureted vehicles, mechanical pumps attached to the engine used suction to pull fuel from the tank and pressurize it for the carburetor. Modern gasoline vehicles have an electric fuel pump in the fuel tank that pressurizes the fuel for use in a fuel injection system.
- Diesel engines use a lift pump that brings fuel from the tank to the diesel injection pump, which turns the lower-pressure delivery of fuel into extremely high pressure for a diesel injector. Most lift pumps today are electrical.
- Bad fuel pump symptoms include a sharp whining sound from the fuel tank, difficulty starting the vehicle, hesitation, lack of power or stalling during acceleration, and a fuel gauge that does not work correctly.
- A fuel pressure test can help determine if the fuel pump is the problem, and changing the fuel filter is always the first step to take. Most auto shops offer a fuel pressure testing kit, and preferred shops in your area can help if you’re unsure how to test or perform the task.
- In modern vehicle fuel pumps, the pump assembly usually contains the fuel level sending unit as well, so if the fuel gauge does not work correctly, changing the fuel pump can rectify the issue.
- If the fuel pump fails, the car may not start at all, and pumps can die without warning. A prime cycle usually occurs for 3-5 seconds when the key is turned on, so if you don’t hear the pump turn on, the fuel pump is suspect.
- The cost of replacing a fuel pump depends on several factors, including the vehicle’s parts cost, which ranges between $75 and $250, and the mechanic’s cost, which ranges between $400 and $600. The actual replacement can take between 1 to 6 hours, depending on the mechanic’s expertise and tools. Replacing a fuel pump is considered an intermediate-level task.
How Often Do You Need To Change Your Fuel Pump
A fuel pump replacement cost isn’t cheap. So it begs the question, how often does it need to be changed? Here’s the good news, fuel pumps do not need to be replaced very often. Usually, a fuel pump would last up to 100,000 miles, and some even double that. You rarely come across a need to repair or replace it.
That being said, a fuel pump replacement cost doesn’t need to be on your annual bill. If you buy a used or drive your car until its mileage reaches close to 100,000 miles, that’s when you need to think about a replacement.
